It has always been a concern for those in the food service industry to efficiently and safely maintain and control the heat suplied to food such as that served from an open warming well or a closed oven. One aceptable method for heating food resides in the use of a high temperature, tubular heating cable which is strung or wrapped repeatedly back and forth at regular intervals on a well or oven framework beneath a conductive metal surface. Such heating cable is typically comprised of a high resistance nichrome conductor, an insulation layer of mica tape, a wrap of Teflon impregnated glass tape, a fiberglass braid for strength and an outermost protective jacket. The heating cable is connected with suitable electrical thermostat controls and is connected to a source of electrical utility power so as to convert electrical energy into heat.
Unfortunately, use of the tubular heating cable as described above poses a number of problems. One of the drawbacks exists in the labor intensive efforts required to manually string the cable. Another drawback is found in the serviceability of the cable which is difficult to access once installed. Perhaps the most critical problem lies in the inefficiency of the heating cable to provide uniform heat to the food in the trays or oven. Uneven high temperatures sometimes result in undesirable warping of the conductive metal surface.
Accordingly, it remains desirable to provide an improved food heating unit which offers a greater efficiency in heat distribution to certain zones with improved control therein. It is also desirable to provide an improved food warming and holding unit which is simple to assemble, and which utilizes common parts which are easy to service and/or replace. It remains further desirable to employ a heating element which will retain the stiffness of the conductive metal surface.